Though narcotic analgesics and their antagonists are widely used for medical and illicit purposes, comparatively little is known about the effects of these drugs on various acquired behaviors; further, very little is known about the behavioral effects of these drugs in combination with other, non-narcotic, drugs that are in common used. The present project will attempt to more fully characterize the behavioral pharmacology of these drugs in experimental animals and will attempt to specify significant interactions between the behavioral effects of narcotics and narcotic antagonists and the effects of representative stimulants, tranquilizers, sedative hypnotics, and antidepressants. The project will focus on schedule-controlled behaviors maintained by food or water presentation, behaviors maintained by postponement or termination of aversive events (avoidance/escape), behaviors suppressed by aversive events (punishment), and behaviors maintained, seemingly anomolously, by presentation of the same aversive events. We will study the effects of acutely administered narcotics and narcotic antagonists on a variety of acquired behaviors, and will study the development of tolerance to the behavioral effects of these drugs with particular reference to differences in tolerance development that may depend on the types of behavior studied. We will also study interactions in the behavioral effects of narcotics with their pharmacological antagonists, and interactions in the effects of these drugs with those of amphetamines, barbiturates, tranquilizers, and anti- depressants.